NUTLEY, NJ--Vesanoid (treti-noin, all-trans-retinoic acid) has
become the first retinoid to receive a cancer treatment indication
from the US Food and Drug Administration. The new agent, from
Hoffmann-La Roche, is indicated for induction of remission in
patients with acute promyelocytic leukemia (APL) who are refractory
to or have relapsed from anthracycline chemotherapy, or for whom
anthracy-cline chemotherapy is contraindicated.

Vesanoid is for induction of remission only, and it should be
followed by an accepted form of remission consolidation and/or
maintenance therapy.

In APL patients achieving complete remission, the agent produces
an initial maturation of the primitive promye-locytes derived
from the leukemic clone, followed by marrow repopulation by normal,
polyclonal hematopoietic cells.

In an open-label, uncontrolled study from Memorial Sloan-Kettering
Cancer Center and two cohorts of compassionate cases treated by
multiple investigators under the auspices of the NCI, complete
remissions among previously treated patients ranged from 50% to
80%, compared with rates of 30% to 50% previously reported for
cytotoxic chemotherapy of APL in relapse.

Median survival for Vesanoid-treated patients ranged from 5.8
to 10.8 months, compared with less than 6 months in studies of
cytotoxic chemotherapy.

In clinical trials, about 25% of Vesanoid-treated patients experienced
retinoic acid-APL (RA-APL) syndrome, which is characterized by
fever, dyspnea, weight gain, radiographic pulmonary infiltrates,
and pleural or pericardial effusions. High-dose steroids given
at the first suspicion of the syndrome appear to reduce morbidity
and mortality.

During Vesanoid treatment, about 40% of patients will develop
rapidly evolving leukocytosis. Patients who present with leukocytosis
at diagnosis have an increased risk of a further rapid increase
in WBC counts, which is associated with a higher risk of life-threatening
complications. In these cases, adding full-dose chemotherapy to
the Vesanoid regimen may be recommended.